New AK-47

Just bought a new AK but I don't know much about it and was hoping some of you may be able to help me out. Sierra Arms Int. Wellington, Nev. Mod AUSA is what is stamped on the receiver. Any of you heard of these or know anything about them?

It looks like a parts kit built on an Armory USA receiver. Built by Sierra Arms..(never heard of them). Chances are it's a Romanian parts kit. AUSA receivers are high quality and it looks like it's built well. Someone has put as much money in aftermarket parts on it as what the rifle cost originally. The buttstock is Bulgarian. Some closer pics of the other side of the rifle and front sight base and I could probably tell you for sure what country the parts kit came from.